The technology of 3D printing allows many users to make their designs and prototypes come to life, allowing you to make anything you can imagine. However, when you start incorporating food containers and heat-safe models into your 3D printing, you may be playing with fire.
ABS filament is not microwave-safe. Although it has some level of thermal stability, this material can melt and shrink under intense heat, releasing harmful chemicals in the process. Some ABS filaments claim to be microwave-safe, but it is better to err on the side of caution.
So, let’s get into the details and discuss why it is better not to microwave ABS and other plastics. It will also talk about what happens when you put ABS filament or prints into the microwave.
What Is ABS Filament?
First, it is essential to discuss what an ABS filament is to understand its chemical properties.
ABS filament is a thermoplastic polymer used in 3D printing and other applications. It comprises three types of monomers — acrylonitrile, butadiene, and styrene to make a stable polymer. Each monomer contributes to the filament’s overall properties.
Aside from 3D printing, ABS (Acrylonitrile Butadiene Styrene) is also a common material in manufacturing instruments, automotive parts, appliances, toys, and many other products. It is also common for making 3D medical models.
Acrylonitrile Monomer Contributes To Thermal Stability
As we have mentioned, the three monomers of ABS contribute to its overall properties. When manufacturers make ABS, they can adjust the percentage of each monomer accordingly to achieve the properties sought after.
High acrylonitrile content leads to thermal stability and chemical and heat resistance. This monomer allows some ABS filaments or products to resist heat better than those with lower acrylonitrile content. However, some people may include more of the other monomers to achieve specific properties.
Should You Microwave ABS Filament?
However, even if the acrylonitrile content gives the filament some level of thermal stability and heat resistance, would it be recommended for you to microwave ABS filament?
You should not microwave ABS filament. Although it has a higher melting point than PLA, it can still warp or shrink under heat. Besides that, it also has styrene and other chemicals that, when heated or burned, may be toxic for humans.
What Is the Melting Point of ABS Filament?
The melting point and glass transition temperatures of a filament help determine its ability to resist heat.
ABS plastic has a melting point of around 200°C (392°F). The plastic or filament may turn from a solid to a liquid state at this temperature. Meanwhile, a microwave has no accurate or absolute highest temperature, so you can never tell how hot ABS would get in a microwave.
Microwaves do not have an absolute maximum temperature because instead of having heating elements, they excite the molecules inside an object, which causes it to heat up.
Hence, while most food gets to around 100°C (212°F) or so inside a microwave, there is no absolute way to say that an ABS filament would only get that hot as well. The maximum temperature depends on the object itself. Thus, there is a high chance of overshooting the melting point.
That said, we can see why it would be risky to place a filament in a microwave– it is difficult to control the temperature, and the object could heat up too much, releasing toxic gasses.
Should You Dry ABS and Other Filaments in Microwave?
Filaments tend to absorb moisture, which can affect printing. Hence, you need to dry them before usage if left exposed. So, can you use a microwave to dry ABS filament?
You should not dry ABS filament or other filaments in a microwave. It is hard to control the temperature in the microwave, making it more likely that the filament will overheat or melt. Microwaving ABS may also lead to the release of toxic fumes in the microwave.
What Happens When You Microwave ABS Filament?
Well, what if you try to microwave ABS? What exactly happens?
When you microwave ABS filament, it can melt or warp inside a microwave, especially when the temperature exceeds the melting point or glass transition temperatures. ABS prints may also shrink when microwaved. There may also be toxic fumes or particles released.
Although ABS may be able to hold up for a bit inside the microwave because it has a higher melting point than PLA or other filaments, at some point, it may overheat because a microwave has no maximum temperature.
Aside from that, the longer you heat an object made from ABS, the more toxic fumes may be released.
What Are the Risks of Microwaving ABS Filament?
As we have mentioned, there is a possibility that the ABS filament will release toxic fumes when heated. A study found that ABS creates more particles and volatile organic compounds (VOCs) than PLA when heated and processed filament.
When you microwave ABS, you risk releasing these VOCs since the filament will get hot after a few minutes. That’s the reason why, when using ABS, it is essential to work in a well-ventilated area to avoid exposure or inhalation.
Indeed, the same study found that ABS filaments tend to release styrene particles, which is a possible carcinogen or cancer-causing material.
Can You Microwave ABS With Food?
3D printing offers so many possibilities that you may think of making a personal mug or food container. Let’s say you did that, and now you are considering popping it in the microwave with food. Is that a good idea?
You cannot microwave ABS with food. Even though there may be food grade or food-safe ABS on the market, this polymer is known to be toxic and may inadvertently release toxins that can harm you. Besides that, ABS itself is not microwave-safe.
Not only that, 3D printed materials are not recommended for food storage. That’s not only because of possible toxins but also because there may be gaps or pores in which bacteria may lodge and proliferate.
It is not recommended to use ABS filament or print inside a microwave – either for drying, by itself, or with food. The risks of toxic fumes outweigh the possible chance that the ABS will have enough Acrylonitrile contents to resist the microwave’s heat. Not only that, the quality of the ABS may change when you microwave it, either through melting, warping, or shrinking.
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I started 3D printing since 2013 and have learned a lot since then. Because of this I want to share my knowledge of what I have learned in the past years with the community. Currently I own 2 Bambulab X1 Carbon, Prusa SL1S and a Prusa MK3S+. Hope you learn something from my blog after my years of experience in 3D printing.